1. Field of the Invention
This invention relates to a method and apparatus for controlling a brushless motor, and more particularly to a method and apparatus of the kind described above which can drive a brushless motor with high operating efficiency.
2. Description of the Related Art
A prior art method commonly used hitherto for controlling a brushless motor has been such that an exciting signal representing a duty ratio or duty factor of 1/3 is supplied to the brushless motor over its entire rotation speed range including its low rotation speed range and its high rotation speed range so as to control the rotation speed of the brushless motor according to the value of the current.